It is important to find out if this is a laminate “wood” floor, a new hardwood floor or an old varnished one that hasn’t been re-finished in a few dozen years.
If it is one of the newer laminate wood floors the top “wear layer” is very much like AFG’s formica counter tops. bleach and a green scrubby pat will make short work of it. Bleach is much more aggressive when hot. I frequently heat it in a plastic bottle set in near boiling water for a few mins.
If it is a newer floor it is likely coated with a urethane sealant and gloss coat. The ammonia may work for you. Unfortunatly some printing inks have a real affinity for synthetic finishes. I have seen vinyl floors pick up purple dye stains that literally discolor all the way through the wear layer making the stain almost practicly impossible to remove.
Luckily, on varnished (or urethaned) floors, the offending stain can usually be lightly sanded away Then the top re-waxed and buffed to match the overall shine of the floor.
Save that for last though. Like Picunurse suggested, try a mild floor cleaner first. Then a light wax stripper. Next a little ammonia or rubbing alcohol (CAUTION alcohol will “cloud” many finishes) on a soft rag before breaking out the 120 grit.
Do not sand all the way to bare wood as you will surely leave a lighter spot on the finish that will look worse than before.